Source : Webster's Revised Unabridged Dictionary (1913)

Semiotics \Se`mi*ot"ics\, n.
   Same as {Semeiotics}.

Semeiotics \Se`mei*ot"ics\, or Semiotics \Se`mi*ot"ics\, n.
   Semeiology.

Source : WordNet®

semiotics
     n : (philosophy) a philosophical theory of the functions of
         signs and symbols